水稻的主要生育期,土壤处于淹水状态,通常采用表层撒施化肥的方法,由于氧化、还原作用的交替进行而引起脱氮和养分的流失,肥料的吸收利用率很低。特别是随着碳酸氢铵的供应量逐年增加,问题显得更为突出。因此,研究经济合理的施肥技术,提高化肥的吸收利用率,是水稻增产的关键措施。近年来国内外研究水稻深层施肥法,取得了较好的增产效果。我区一些地方以往也有“塞秧兜”、氨水作底肥、先施肥后薅秧的经验,说明肥料深施是一项值得重视的技术。我站1973年开始试验,初步看出球肥深施,有水稻稳长、促进穗大粒多、成穗率和谷草比高等优点。但由于追肥太迟,增产不够显著。因我区主要是多穗型品种,前期养 The main growth period of rice, the soil is flooded state, usually using the method of surface fertilization of chemical fertilizers, due to the oxidation and reduction of alternation caused by the loss of nitrogen and nutrients, fertilizer absorption and utilization rate is low. Especially with the supply of ammonium bicarbonate increased year by year, the problem is even more prominent. Therefore, the study of economic and reasonable fertilization technology, improve the absorption and utilization of chemical fertilizers, is the key measures to increase rice yield. In recent years, domestic and international research on deep fertilization of rice, and achieved good yield. In some places in our district, there were also “seedling pocket” in the past, the experience of using ammonia water as the base fertilizer and the first application of fertilizer after planting seedlings, indicating that fertilizer application is a worthy technique. I started the pilot station in 1973, initially found that deep application of fertilizer, a stable rice, and promote large spikelets, spike rate and grain to straw ratio higher advantages. However, due to too late dressing, the increase is not significant enough. Due to my area is mainly multi-spike varieties, pre-support